Stationary LARP (“Laser Activated Remote Phosphor”) systems are known, in which a wavelength-converting phosphor is illuminated across a large area by a stationary blue laser beam (“primary light beam”) and in the process converts the laser light partially into yellow light (“secondary light”). The non-converted blue primary light and the converted yellow secondary light together give white mixed light. If the phosphor is damaged or even removed completely from the beam path, the primary light can exit the LARP system in greater proportions and, in addition, coherently. To prevent this, it is conventional to use two light detectors that are sensitive to the primary light or the secondary light and to deduce failure of the phosphor on the basis of the ratio of the strengths of their measurement signals. If failure is ascertained, the LARP system can be switched off (“safety switch-off”) or a luminous flux of the primary light can be reduced until safety regulations are complied with (“emergency light operation”). However, this method may have the effect that minor damage to the phosphor is detectable only with difficulty, and a reaction to damage practically results in a malfunction of the LARP system.
WO 2015/000006 A1 discloses a vehicle headlight having at least one laser light source, the laser beam of which is deflected, via a micromirror that is pivotable about at least one axis, to a light-emitting surface having a light-conversion phosphor so as to generate at said light-emitting surface a light-emitting image in a scanning fashion, which can be projected onto a driving lane via an optics. In this headlight, at least one photosensor is positioned with respect to the light-emitting surface having the light-conversion phosphor such that it captures, in predetermined deflection orientations of the micromirror, a secondary laser beam emanating from the light-emitting surface and is adapted for emitting a signal.